Last week, RTÉ's 'CrimeCall' programme re-enacted the last known movements of the couple and showed CCTV footage of them together.

Investigating gardaí and the missing man's parents, Joseph and Helen, also appealed for information. Mr Maughan told the Irish Independent that he believes they were murdered because his son "knew too much" about a gang murder last year.

Gardaí are understood to have received reliable intelligence that the couple were murdered by up to five members of a drug gang. The gang leader is a settled Traveller and prime suspect for another murder.

It is understood that the gang attacked the couple when they realised they were about to leave Gormanston - but may not have intended to kill them.

A source close to the gang has claimed that the leader's elderly mother helped to restrain Anna Varslavane while her son and his cronies attacked William.

Sources claimed that the young woman was beaten over the head with a hammer while she tried to phone for help.

Bodies

In the past week, the Maughan family have received information which may help gardaí locate the bodies.

"We know that they are both gone and just want them brought back so that we can give them a Christian funeral," Joseph Maughan said.

"That is why we are appealing to anyone with a conscience to come to us or the gardaí with any information." He added: "I believe a certain group of people in Gormanston know what happened to William and Anna.

"My son knew something that he should not have known, that is why they were taken."

Anyone with information is asked to contact Ashbourne Garda Station on 01-8010600 or the Missing Persons Helpline on 18904425852.